Uses of Electromagnets — Reading Comprehension

Grades

Standards

MS-PS2-3

About This Reader

This engaging middle school science passage explores the uses of electromagnets, aligned with NGSS standard MS-PS2-3. Students learn how electromagnets transform electric current into magnetic force and see how this principle powers devices such as junkyard cranes, doorbells, MRI machines, headphones, and maglev trains. The passage explains the system interactions and mechanisms behind electromagnets, provides real-world quantitative details, and connects the topic to broader scientific principles of forces and energy. With direct, student-friendly language, the passage encourages scientific thinking by explaining cause-and-effect chains and integrating evidence from multiple applications. Activities include comprehension questions, writing prompts, and graphic organizers. All materials are audio integrated for accessibility, and both English and Spanish versions are provided for differentiated instruction.

CONTENT PREVIEW

electromagnet-3 — Illustration of electromagnet applications in daily life

Electromagnets are essential components in modern technology, providing powerful and controllable magnetic forces for a variety of applications. In many junkyards, massive cranes use electromagnets to lift, move, and drop heavy pieces of scrap metal with precision. This ability to turn magnetism on and off is crucial to sorting and transporting materials efficiently. Understanding how electromagnets work reveals the science behind many devices we use every day.

How Electromagnets Work

A magnet is an object that produces a magnetic field, attracting certain metals like iron. An electromagnet is made by passing an electric current through a coil of wire, usually wrapped around a piece of iron. When current flows, it generates a magnetic field, which can be made stronger by increasing the number of coils or the amount of current. Unlike permanent magnets, electromagnets can be switched on and off by controlling the flow of electricity. This mechanism allows for precise control over magnetic forces, which is essential for many machines. For example, a junkyard crane operator can activate the electromagnet to pick up metal and then deactivate it to drop the load exactly where needed.

Applications of Electromagnets

Electromagnets are found in many devices that convert electrical energy into motion, sound, or other forms of work. In doorbells and buzzers, small electromagnets pull a metal arm to create sound when someone presses the button. Speakers and headphones use electromagnets to turn electrical signals into vibrations, producing sound waves that we can hear. In MRI machines, extremely strong electromagnets create magnetic fields up to 60,000 times stronger than Earth's field, allowing doctors to image the inside of the human body without surgery. Maglev trains use large electromagnets to levitate above the tracks and move at speeds over 300 km/h, reducing friction and allowing for fast, smooth travel. These examples show how controlling magnetism through electricity has transformed transportation, medicine, and communication.

Systems and Interactions

Electromagnets are often parts of larger systems, interacting with other components for specific purposes. In computer hard drives, tiny electromagnets help store and retrieve data by changing the magnetization of small regions on spinning disks. Electric locks use electromagnets to secure doors until an authorized signal is received, increasing safety in buildings. In particle accelerators, powerful electromagnets steer beams of particles at nearly the speed of light for experiments in physics. All these systems rely on the relationship between electricity and magnetism, a principle called electromagnetic induction. This scientific understanding drives ongoing innovations in fields from transportation to healthcare.

By studying electromagnets, scientists and engineers have developed technologies that shape our world. The ability to control magnetic forces with electricity connects to broader scientific ideas about energy transfer, forces, and the structure of matter. As new discoveries are made, electromagnets will continue to play a key role in solving problems and advancing modern life.

Interesting Fact:
Some maglev trains in Japan use electromagnets to reach speeds of over 600 km/h, making them among the fastest trains in the world!

What is the main advantage of an electromagnet compared to a permanent magnet?

It can be turned on and off with electricity.It is always magnetic.It is made only from iron.It cannot attract metal.

Which device uses electromagnets to produce sound?

Hard driveSpeakerMaglev trainElectric lock

According to the passage, what happens when the electric current stops flowing in an electromagnet?

The magnet becomes even stronger.The electromagnet turns off.It attracts more metal.It starts to make sound.

In the context of the passage, what does 'electromagnetic induction' mean?

Creating electricity by moving a magnet.Making a magnet by winding wire around plastic.Turning on a lightbulb with a switch.Producing sound from a speaker.

What is the function of electromagnets in MRI machines?

To produce strong magnetic fields for medical imaging.To play music in the hospital.To keep doors locked.To power maglev trains.

Why do maglev trains use electromagnets?

To float above the tracks and travel quickly.To make announcements to passengers.To store computer data.To open electric locks.

Which of the following best describes the relationship between electricity and magnetism in electromagnets?

Electricity creates magnetism in the coil.Magnetism creates new metals.Electricity removes magnetism from iron.Magnetism and electricity are not related.

How do electromagnets help make computers work, according to the passage?

They store and retrieve data in hard drives.They play loud music.They open computer screens.They control electric locks.

True or False: Electromagnets are used only in junkyard cranes.

TrueFalse

True or False: Increasing the number of coils in an electromagnet makes its magnetic field stronger.

TrueFalse